OK, since someone asked for this, you've got it! This is about the difference between "your" and "you're."
your - possessive - belonging to YOU!
you're - contraction - short form of "you are"
You're going to the store, where you expect to spend all of your money.
(You are going to the store, where you expect to spend all of the money belonging to you.)
Another easy way to remember this is that whenever you see the apostrophe in a contraction, it represents a word which has been partially omitted. You're=you are, don't=do not, wasn't=was not, isn't=is not, they've=they have. Knowing this can help you determine whether or not a contraction is appropriate. Just read the sentence aloud, using the long form of the contraction.
Example: You are going to the store, where you expect to spend all of you are money.
You can HEAR which one is correct. #1 should be You're. #2 should be your.